1. Field of the Invention.
This invention relates generally to Artificial Body Members, and more specifically to artificial intraocular lenses for implanting or mounting within the eye.
2. Description of the Prior Art.
The concept of the use of intraocular lenses for the correction of aphakia has a long history. The actual practice of implanting lenses is relatively recent. Much of the pioneering work was performed by Harold Ridley in London and by Binkhorst in the Netherlands. A comprehensive history of the development and results of the intraocular implant lens is presented in a thesis by Marcel Eugene Nordlohne and reproduced in Documenta Ophthalmologica, Vol. 38, Issue 1, Dec. 16, 1974.
A variety of intraocular lenses of the general type of the present invention are also described in the patent literature. These include the patents to:
Lieb, W. A. 2,834,023 ANTERIOR CHAMBER LENSES FOR REFRACTIVE CORRECTION OF APHAKIA PA1 Deitrick, R. E. 3,711,870 ARTIFICIAL LENS IMPLANT PA1 Fedorov, S. N. 3,673,616 ARTIFICIAL ANTERIOR CHAMBER LENS PA1 Flom, L. 3,866,249 POSTERIOR CHAMBER ARTIFICIAL INTRAOCULAR LENS PA1 Otter, K. 3,906,551 ARTIFICIAL INTRAOCULAR LENS SYSTEM PA1 Potthast, E. W. 3,913,148 INTRAOCULAR LENS APPARATUS
Most of the patents listed above are addressed to the problem of mounting the lens within the eye so that it can perform its intended function with a minimum of trauma to the eye. This has been a major problem from the earliest of times. An early report by Schiferli in 1795 described an attempt by Casaamata to introduce a glass lens into the eye after a cataract operation. The lens immediately slid back towards the fundus of the eye.
The problem of mounting a biologically tolerable lens has continued to plague the development of the implant practice. Previous lenses have relied on mechanical pressure fixation to hold the lens within the eye. Using this type of fixation requires a balance between the pressure necessary to stabilize the lens within the eye, holding it in place, and that amount of pressure that will cause tissue necrosis. Thus a lens cannot be mechanically fixed to ocular tissue with a great deal of pressure or the tissue will necrose and be damaged. All prior pupillary fixation lenses have thus erred on the side of being too loose and therefore require an additional fixation such as a suture or wire being placed through the lens.